docs: Overhaul contributor infrastructure and add GitHub templates

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,29 @@
+---
+name: Bug Report
+about: Create a report to help us improve Durable Workflow
+title: "[Bug] "
+labels: bug
+assignees: ''
+
+---
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**To Reproduce**
+Steps to reproduce the behavior:
+1. Define workflow '...'
+2. Start execution with payload '...'
+3. See error
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Environment:**
+ - PHP Version: [e.g. 8.1]
+ - Laravel Version: [e.g. 10.0]
+ - Durable Workflow Version: [e.g. v2.0.0-rc.31]
+ - OS: [e.g. Ubuntu]
+
+**Additional context**
+Add any other context about the problem here, such as stack traces or logs.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,20 @@
+---
+name: Feature Request
+about: Suggest an idea for this project
+title: "[Feature] "
+labels: enhancement
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen.
+
+**Describe alternatives you've considered**
+A clear and concise description of any alternative solutions or features you've considered.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,29 @@
+## Description
+<!-- Please include a summary of the change and which issue is fixed. -->
+<!-- Please also include relevant motivation and context. -->
+
+Fixes # (issue)
+
+## Type of change
+- [ ] Bug fix (non-breaking change which fixes an issue)
+- [ ] New feature (non-breaking change which adds functionality)
+- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
+- [ ] This change requires a documentation update
+
+## How Has This Been Tested?
+<!-- Please describe the tests that you ran to verify your changes. -->
+<!-- Provide instructions so we can reproduce. -->
+
+- [ ] `composer test`
+- [ ] `composer stan` (PHPStan)
+- [ ] `composer ecs` (Code Style)
+
+## Checklist:
+- [ ] My code follows the style guidelines of this project
+- [ ] I have performed a self-review of my own code
+- [ ] I have commented my code, particularly in hard-to-understand areas
+- [ ] I have made corresponding changes to the documentation
+- [ ] My changes generate no new warnings
+- [ ] I have added tests that prove my fix is effective or that my feature works
+- [ ] New and existing unit tests pass locally with my changes
+- [ ] If this touches replay/payload-codec logic, I have updated regression-corpus fixtures

CONTRIBUTING.md

@@ -1,20 +1,84 @@
-# Contributing
+# Contributing to Durable Workflow
 
-Run ECS in check mode, PHPStan, and focused PHPUnit coverage for changed code.
+First off, thank you for considering contributing to Durable Workflow! It's people like you that make this engine a great tool for the Laravel community.
 
-Replay and payload-codec fixes also follow the organization
-[regression-corpus contract](https://github.com/durable-workflow/.github/tree/main/regression-corpus).
-Use one-case golden histories under `tests/Fixtures/V2/GoldenHistory/` whenever
-the query-state replay runner can consume them. Cold worker replay evidence
-belongs under `tests/Fixtures/V2/ReplayRegression/`; each fixture names an
-autoloadable workflow and is executed through the production
-`WorkflowFiberRunner` using either persisted history or a worker command
-sequence. Shared codec evidence belongs under `tests/Fixtures/V2/CodecRegression/`
-and in every applicable official binding.
+## Development Environment Setup
 
-Fixtures preserve protocol version, value and type, framing, and stable failure
-policy. Existing evidence is append-only. Run:
+To set up the project locally:
+
+1. **Clone the repository:**
+   ```bash
+   git clone https://github.com/durable-workflow/workflow.git
+   cd workflow
+   ```
+
+2. **Install dependencies:**
+   Make sure you have PHP 8.1+ and Composer installed.
+   ```bash
+   composer install
+   ```
+
+3. **Set up the Testbench environment:**
+   We use Orchestra Testbench for our testing environment.
+   ```bash
+   composer prepare
+   composer build
+   ```
+
+## Development Workflow
+
+### Code Style & Static Analysis
+
+We enforce strict coding standards using EasyCodingStandard (ECS) and PHPStan. Before submitting a PR, always run:
 
 ```bash
-python scripts/ci/validate-regression-corpus.py --base-ref <target>
+# Check and automatically fix code style issues
+composer ecs
+
+# Run static analysis
+composer stan
+# Alternatively, to run with verbose output:
+composer lint
 ```
+
+### Testing
+
+Tests are written using PHPUnit. Ensure your changes pass existing tests and include new ones if you're adding functionality.
+
+```bash
+# Run the entire test suite
+composer test
+
+# Run only unit tests
+composer unit
+
+# Run only feature tests
+composer feature
+
+# Generate coverage report (requires Xdebug)
+composer coverage
+```
+
+## Regression Corpus & Fixtures
+
+**Important:** Replay and payload-codec fixes must follow the [regression-corpus contract](https://github.com/durable-workflow/.github/tree/main/regression-corpus).
+
+When working with worker replay or shared codecs, adhere to the following rules:
+
+1. Use one-case golden histories under `tests/Fixtures/V2/GoldenHistory/` whenever the query-state replay runner can consume them.
+2. Cold worker replay evidence belongs under `tests/Fixtures/V2/ReplayRegression/`. Each fixture names an autoloadable workflow and is executed through the production `WorkflowFiberRunner` using either persisted history or a worker command sequence.
+3. Shared codec evidence belongs under `tests/Fixtures/V2/CodecRegression/` and in every applicable official binding.
+4. Fixtures must preserve protocol version, value and type, framing, and stable failure policy.
+5. Existing evidence is **append-only**. Do not modify existing evidence unless explicitly directed by maintainers.
+
+To validate your regression corpus additions against a target branch, run the validation script:
+
+```bash
+python scripts/ci/validate-regression-corpus.py --base-ref main
+```
+
+## Pull Request Process
+
+1. Follow the Pull Request template provided when opening a PR.
+2. Update the README.md or docs if your changes impact user-facing APIs.
+3. The CI pipelines will automatically run on your PR. You must have all CI checks (ECS, PHPStan, PHPUnit) passing before your PR can be merged.